中国物理B ›› 2011, Vol. 20 ›› Issue (4): 43105-043105.doi: 10.1088/1674-1056/20/4/043105

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MRCI study of spectroscopic and molecular properties of X1Σg+ and A1Πu electronic states of the C2 radical

张小妞, 施德恒, 孙金锋, 朱遵略   

  1. College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
  • 收稿日期:2010-09-13 修回日期:2011-01-04 出版日期:2011-04-15 发布日期:2011-04-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 10874064) and the Program for Science & Technology Innovation Talents in Universities of Henan Province of China (Grant No. 2008HASTIT008).

MRCI study of spectroscopic and molecular properties of X1$\varSigma$g+ and A1$\varPi$u electronic states of the C2 radical

Zhang Xiao-Niu(张小妞), Shi De-Heng(施德恒), Sun Jin-Feng(孙金锋), and Zhu Zun-Lue(朱遵略)   

  1. College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
  • Received:2010-09-13 Revised:2011-01-04 Online:2011-04-15 Published:2011-04-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 10874064) and the Program for Science & Technology Innovation Talents in Universities of Henan Province of China (Grant No. 2008HASTIT008).

摘要: The potential energy curves (PECs) of X1Σg+ and A1Πu electronic states of the C2 radical have been studied using the full valence complete active space self-consistent field (CASSCF) method followed by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in conjunction with the aug-cc-pV6Z basis set for internuclear separations from 0.08 nm to 1.66 nm. With these PECs of the C2 radical, the spectroscopic parameters of three isotopologues (12C2, 12C13C and 13C2) have been determined. Compared in detail with previous studies reported in the literature, excellent agreement has been found. The complete vibrational levels G(v), inertial rotation constants Bv and centrifugal distortion constants Dv for the 12C2, 12C13C and 13C2 isotopologues have been calculated for the first time for the X1Σg+ and A1Πu electronic states when the rotational quantum number J equals zero. The results are in excellent agreement with previous experimental data in the literature, which shows that the presented molecular constants in this paper are reliable and accurate.

关键词: potential energy curve, spectroscopic parameter, molecular constant, isotope effect

Abstract: The potential energy curves (PECs) of $X^{1}\varSigma _{\rm g}^{ + }$ and $A^{1}\varPi_{\rm u}$ electronic states of the C$_{2}$ radical have been studied using the full valence complete active space self-consistent field (CASSCF) method followed by the highly accurate  valence internally contracted multireference configuration interaction (MRCI) approach in conjunction with the aug-cc-pV6Z basis set for  internuclear separations from 0.08~nm to 1.66~nm. With these PECs of the C$_{2}$ radical, the spectroscopic parameters of three isotopologues  ($^{12}$C$_{2}$, $^{12}$C$^{13}$C and $^{13}$C$_{2})$ have been determined. Compared in detail with previous studies reported in the literature,  excellent agreement has been found. The complete vibrational levels $G(\upsilon$), inertial rotation constants $B_{\upsilon }$ and centrifugal  distortion constants $D_{\upsilon }$ for the $^{12}$C$_{2}$, $^{12}$C$^{13}$C and $^{13}$C$_{2}$ isotopologues have been calculated for the  first time for the $X^{1}\varSigma _{\rm g}^{ + }$ and $A^{1}$$\varPi_{\rm u}$ electronic states when the rotational quantum number $J$ equals zero. The results are in excellent agreement with previous experimental data in the literature, which shows that the presented molecular  constants in this paper are reliable and accurate.

Key words: potential energy curve, spectroscopic parameter, molecular constant, isotope effect

中图分类号:  (Electron correlation calculations for diatomic molecules)

  • 31.15.vn
31.50.Df (Potential energy surfaces for excited electronic states) 31.50.Bc (Potential energy surfaces for ground electronic states)